How to animate an expanding network using Animation Nodes 2.0?
Let's have fun with Animation Nodes then !

Teaser :



Teaser 2 :



Get the blend file here :





First, let's create a loop to instantiate the spheres and make them grow to their normal scale depending on a certain falloff :
If you want to find a node by name, type CTRL + A and then the name of the node you are looking for.

In the topbar, go to Add > Subprogram > Loop

Add a new iterator of type "Object List" and a new parameter of type "Float" and then put the nodes like the screen after.

Don't forget to click "New Generator output" and choose "Float" to generate a float list which will help us instantiate the growing bars between nodes.



Next up, let's grow the bars. Create a new loop. Add an iterator of type "Edge Indices List", a new parameter of type "Vector List" and a new parameter of type "Float List".

We will be using the evaluation time to make the bars grow between the first node, which is supposed to have already appeared, and the second node, which will appear when its correspond float value reaches 0.

Add a new generator output of type "Spline List" in order to output them from this loop. We only want to add to this spline list the splines where the bar can indeed be visible. Thankfully yhis node has a hidden condition input.

While selecting the "Spline List" generator output node, press N on your keyboard to make the right hand panel appear. go to the item subpanel and check the screen icon on the right of the "Condition input". Illustration :





Now let's finish this with the main loop :

Add a "Viewport input" node which will let you modify values in your node tree directly from the viewport.
Add a sphere object in object mode and choose it inside your instancer node. You can create invoke nodes of your subprograms by clicking on the first node and pressing W then choosing "Create invoke node"

Don't forget to set a new material for your spline or else the bars will stay white.